How to fix AttributeError in App Engine Flex when using grpc and cloud-datastore?

Question

When I deploy a python3 application using Google App Engine Flex I get the following error:

  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/home/vmagent/app/run.py", line 8, in <module>
    app = create_app(os.getenv('FLASK_CONFIG') or 'default')
  File "/home/vmagent/app/application/__init__.py", line 43, in create_app
    from .main import main as main_blueprint
  File "/home/vmagent/app/application/main/__init__.py", line 5, in <module>
    from . import cron_jobs, views
  File "/home/vmagent/app/application/main/cron_jobs.py", line 4, in <module>
    from google.cloud import datastore
  File "/env/lib/python3.6/site-packages/google/cloud/datastore/__init__.py", line 60, in <module>
    from google.cloud.datastore.batch import Batch
  File "/env/lib/python3.6/site-packages/google/cloud/datastore/batch.py", line 24, in <module>
    from google.cloud.datastore import helpers
  File "/env/lib/python3.6/site-packages/google/cloud/datastore/helpers.py", line 29, in <module>
    from google.cloud.datastore_v1.proto import datastore_pb2
  File "/env/lib/python3.6/site-packages/google/cloud/datastore_v1/__init__.py", line 18, in <module>
    from google.cloud.datastore_v1.gapic import datastore_client
  File "/env/lib/python3.6/site-packages/google/cloud/datastore_v1/gapic/datastore_client.py", line 18, in <module>
    import google.api_core.gapic_v1.client_info
  File "/env/lib/python3.6/site-packages/google/api_core/gapic_v1/__init__.py", line 26, in <module>
    from google.api_core.gapic_v1 import method_async  # noqa: F401
  File "/env/lib/python3.6/site-packages/google/api_core/gapic_v1/method_async.py", line 20, in <module>
    from google.api_core import general_helpers, grpc_helpers_async
  File "/env/lib/python3.6/site-packages/google/api_core/grpc_helpers_async.py", line 145, in <module>
    class _WrappedStreamUnaryCall(_WrappedUnaryResponseMixin, _WrappedStreamRequestMixin, aio.StreamUnaryCall):
AttributeError: module 'grpc.experimental.aio' has no attribute 'StreamUnaryCall'

My requirements.txt file include the following:

google-cloud-datastore==1.12.0
grpcio==1.27.2

The reason I am using grpcio version 1.27.2 instead of the most recent 1.29.0 is because of the information shown here

Can somebody help?

Answer 1

I just encountered the same issue, so this may help you out. I've noticed that google-api-core is also a dependency and it was recently updated (specifically around the grpc_helpers_async), so I just pinned it to version 1.17.0 and it resolved the issue. Just add this to your requirements:

google-api-core==1.17.0